Dishwasher including water guide with water pipe connector

ABSTRACT

The present invention relates to a dishwasher and a manufacturing method thereof. 
     The dishwasher according to an embodiment of the present invention includes a water guide extending upward from a sump and supplying washing water to an upper nozzle and a top nozzle, and the upper pipe and the top pipe are separately provided to the water guide, so pressure of the washing water applied to the upper pipe and the top pipe can be reduced.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No.10-2018-0001095, filed on Jan. 4, 2018, the entire contents of which isincorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a dishwasher.

Description of the Related Art

In general, a dishwasher is a machine that washes dishes stained withfood or dirt by spraying washing wafers to the dishes. A tub having awashing space may be disposed in dishwashers and a rack assembly forholding dishes may be disposed in the tub. The rack assembly may beprovided to be able to be drawn out of the tub.

Dishwashers may further include a sump that stores washing water,nozzles that spray the water stored in the sump to dishes, and a waterguide that has pipes extending from the sump to the nozzles to guide thewashing water. The pipes include an upper pipe extending from the sumpto a substantially vertical center portion of the tub and a top pipeextending to the upper space of the tub.

In relation to dishwashers in the related art, the applicant(s) hasapplied for a patent as follows.

1. Publication No. (Publication Date): 10-2007-0056281 (Apr. 8, 2013)

2. Title of Invention: Dishwasher and Water Guide of Dishwasher

According to this dishwasher of the related art, the following problemsmay occur.

First, pipes of the water guide are made of plastic, so whenhigh-temperature washing water or steam flows through the pipes, agingoccurs in the pipes due to heat, whereby the pipes are corroded orbroken.

Second, an upper pipe and a top pipe of the pipes are integrally formed,so the amount (pressure) of water flowing through the pipes isrelatively high, and accordingly, there is some possibility that thepipes are damaged.

Third, stress concentration occurs when bending portions are formed onthe plastic pipes, so the bending portions are corroded or broken.

Fourth, high pumping pressure is applied to a connector for fixing apipe to a sump, so water leaks at the connector or the connector isseparated.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to solve the problemsand an object of the present invention is to provide a water guide of adishwasher in which pipes of the water guide are made of a stainlessmaterial to prevent corrosion. In particular, the object is to provide adishwasher in which ductility and hardness of the pipes can be improvedbecause the pipes are made of ductile stainless steel pipes.

Another object of the present invention is to provide a dishwasher thatcan reduce pressure of washing water that is applied to an upper pipe ora top pipe by separately providing the upper pipe and the top pipe suchthat washing water discharged from a sump separately flows to an uppernozzle and a top nozzle.

Another object of the present invention is to provide a dishwasher inwhich the upper pipe and the top pipe are configured as polygonal pipes,thereby being able to prevent interference with the upper pipe and thetop pipe by surrounding components and allow the pipes to be easilysupported by an upper connector.

Another object of the present invention is to provide a dishwasher thatcan easily achieve a bent shape of a water guide and can preventcorrosion due to stress concentration at a bending portion by formingthe bending portion through processing of an upper pipe and a top pipemade of a stainless material.

Another object of the present invention is to provide a dishwasher thatcan prevent separation of a pipe from a connector and can preventleakage of washing water at the connector, through a lower connectorconnecting the pipes and a sump and a clamp coupled to the lowerconnector.

In particular, an object of the present invention is to provide adishwasher that can prevent the front portion of the lower connectorfrom being separated from the sump by making the hardness of a frontportion connected to the sump of the lower connector relatively great.

Another object of the present invention is to provide a dishwasher thatcan prevent leakage of water at a rear portion by bringing the rearportion of a lower connector in close contact with a pipe by making therear portion connected to the pipe of the lower connector relativelysmall.

Another object of the present invention is to provide a dishwasher thatcan prevent leakage of water at a rear portion of the lower connector byproviding that can tighten the rear portion.

The dishwasher according to an embodiment of the present inventionincludes a water guide extending upward from a sump and supplyingwashing water to an upper nozzle and a top nozzle, and the upper pipeand the top pipe are separately provided to the water guide, so pressureof the washing water applied to the upper pipe and the top pipe can bereduced.

The upper pipe may communicate with a first outlet of the sump and thetop pipe may communicate with a second outlet of the sump.

An upper connector supporting the upper pipe and the top pipe may befurther included.

The upper connector includes a connector channel through which washingwater supplied through the upper pipe flows.

The upper connector may further include: a pipe coupling portion towhich the upper pipe is coupled; and a pipe inserting portion in whichthe top pipe is seated, thereby being able to stably supporting theupper pipe and the top pipe.

The upper pipe may be forcibly fitted in the pipe coupling portion,thereby being able to prevent leakage of washing water.

The upper pipe includes: an upper inlet into which the washing waterstored in the sump is introduced; and an upper outlet that is disposedin the pipe coupling portion and through which washing water isdischarged to the connector channel.

A hook formed on a lateral side of the upper connector and a hook insertformed at the bracket and in which the hook is fitted are furtherincluded.

The bracket is bent to surround at least a portion of the rear portionof the upper connector and at least a portion of both lateral sides ofthe upper connector, so it can be stably supported on the upperconnector.

A connector outlet that is disposed at the upper connector to dischargethe washing water in the connector channel is further included, and theconnector outlet extends to be round from the connector channel.

At least one of the upper pipe and the top pipe is made of a stainlessmaterial.

At least one of the upper pipe and the top pipe is a stainless steelpipe including a stainless material and impurities consisting of carbon,manganese, chromium, nickel, and copper, so corrosion resistance againststress of washing water can be improved.

An upper bending portion that is provided at the upper pipe and changesthe flow direction of the washing water; and first and second topbending portions that are provided at the top pipe and changes the flowdirection of the washing water are further included, so flow of washingwater can be easily guided.

The upper pipe and the top pipe are made of a stainless material, soprocessibility of the pipes is excellent and stress corrosion can beprevented.

At least one of the upper pipe and the top pipe is a polygonal pipe, sousability of the space for installing the upper pipe and the top pipecan be improved.

A method of controlling a dishwasher according to another aspectincludes: processing a circular pipe using a raw material plateincluding a stainless material and at least copper; manufacturing arectangular pipe by drawing the processed circular pipe; andmanufacturing the upper pipe and the top pipe having a bent shape bybending the rectangular pipe.

The bending may be performed using a mandrel.

According to the present invention described above, the pipes of thewater guide, that is, the upper pipe and the top pipe are made of astainless steel, so strength and hardness can be reinforced andcorrosion due to thermal deterioration can be prevented.

In particular, a ductile stainless steel pipe, for example, an austenitetype stainless steel pipe is applied to the pipes, so it is possible tosecure high level of ductility in comparison to normal stainless steelpipes, and accordingly, bending processing is easy. The pipes can secureductility and can have high strength and hardness, so a pressureresistance ability is excellent.

The upper pipe and the top pipe are separately provided and washingwater discharged from the sump separately flows to an upper nozzle and atop nozzle, so pressure of washing water applied to the upper pipe orthe top pipe can be reduced. Accordingly, stress corrosion of the pipesdue to water pressure can be prevented.

The upper pipe and the top pipe are polygonal pipes, so interferencewith the upper pipe and the top pipe by surrounding components can beprevented. The polygonal outer surfaces of the upper pipe and the toppipe can be easily supported on an upper connector.

It is possible to easily achieve a bent shape of a water guide and canprevent corrosion due to stress concentration at a bending portion byforming the bending portion through processing of an upper pipe and atop pipe made of a stainless material.

It is possible to prevent separation of a pipe from a connector and canprevent leakage of washing water at the connector, through a lowerconnector connecting the pipes and a sump and a clamp coupled to thelower connector.

In particular, it is possible to prevent the front portion of the lowerconnector from being separated from the sump by making the hardness of afront portion connected to the sump of the lower connector relativelygreat.

It is possible to prevent leakage of water at a rear portion by bringingthe rear portion of a lower connector in close contact with a pipe bymaking the rear portion connected to the pipe of the lower connectorrelatively small.

The clamp is provided in a type of clip that can tighten a rear portionof the lower connector, so leakage of water at the rear portion can beprevented.

A polygonal pipe is manufactured through drawing after a circular pipeis formed using a stainless material and a bending portion of a waterguide can be achieved through a bending process of the manufacturedpolygonal pipe, so elongation and processibility of the pipe can beimproved.

Pipe caving at the bending portion, that is, the phenomenon that thepipe is excessively recessed at the bending portion can be prevented, sostress corrosion can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a cross-sectional view of a dish washer according to anembodiment of the present invention;

FIG. 2 is a view showing a water guide disposed in the dishwasheraccording to an embodiment of the present invention;

FIG. 3 is a perspective view showing the configuration of the waterguide according to an embodiment of the present invention;

FIG. 4 is a cross-sectional view taken along line IV-IV′ of FIG. 3;

FIG. 5 is an exploded perspective view showing the configuration of thewater guide according to an embodiment of the present invention;

FIG. 6 is a rear view showing an upper pipe and a top pipe coupled to anupper connector and a holder according to an embodiment of the presentinvention;

FIG. 7 is a view showing the bracket coupled to the upper connectoraccording to an embodiment of the present invention;

FIG. 8 is a rear view showing the upper pipe and the top pipe coupled tothe upper connector according to an embodiment of the present invention;

FIG. 9 is a cross-sectional view taken along line IX-IX′ of FIG. 8;

FIG. 10 is a view showing the upper pipe and the top pipe connected tothe sump through the lower connector according to an embodiment of thepresent invention;

FIG. 11 is a cross-sectional view taken along line XI-XI′ of FIG. 10;

FIG. 12 is a cross-sectional view taken along line XII-XII′ of FIG. 10;

FIG. 13 is a plan view showing the upper pipe and the top pipe coupledto the lower connector according to an embodiment of the presentinvention;

FIG. 14 is a perspective view showing the clamp coupled to the lowerconnector according to an embodiment of the present invention;

FIGS. 15A and 15B are views showing the configuration of the clampaccording to an embodiment of the present invention;

FIG. 16 is a flowchart showing a method of manufacturing a pipeaccording to an embodiment of the present invention;

FIG. 17 is a perspective view showing a clamp coupled to the lowerconnector according to another embodiment of the present invention;

FIG. 18 is a view showing the configuration of the clamp of FIG. 17; and

FIG. 19 is a perspective view showing a clamp coupled to a lowerconnector according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, detailed embodiments of the present invention will bedescribed with reference to the drawings. However, the spirit of thepresent invention is not limited to the proposed embodiments and otherembodiments may be easily proposed by those skilled in the art withoutdeparting from the scope of the present invention.

FIG. 1 is a cross-sectional view of a dish washer according to anembodiment of the present invention and FIG. 2 is a view showing a waterguide disposed in the dishwasher according to an embodiment of thepresent invention.

Referring to FIGS. 1 and 2, a dishwasher 1 according to an embodiment ofthe present invention includes a case 10 forming the externalappearance, a tub 11 disposed in the case 10 and forming a washingcontainer, a door disposed on the front of the tub 11 andopening/closing the washing container, and a sump 20 disposed on thebottom of the tub 11 and storing washing water.

A plurality of racks 50, 70, and 80 for holding dishes is provided inthe tub 11. The racks 50, 70, and 80 can be drawn forward out of the tub11 by being guided by guide rails (not shown) disposed on the innersides of the tub 11. The racks 50, 70, and 80 include a first rack 50disposed at an upper portion of the tub 11, a second rack 70 disposedover the first rack 50, and a third rack 80 disposed under the firstrack 50.

A lower nozzle 17, an upper nozzle 163, and a top nozzle 170 that spraywashing water supplied from the sump 20 into the washing container aredisposed over the sump 20.

In detail, the lower nozzle 17 is coupled to the top of the sump 20 andsprays washing water to the lower portion of the washing container, andthe sprayed washing water is sprayed toward dishes in the third rack 80.A lower nozzle coupler 19 coupled to the lower nozzle 17 is provided atthe sump 20.

The upper nozzle 163 is disposed at the center portion of the washingcontainer and sprays washing water toward the first rack 50 or thesecond rack 70 and the top nozzle 170 is disposed close to the ceilingof the tub 11 and sprays down washing water toward the first to thirdracks 50, 70, and 80.

A water guide 100 that allows flow of washing water supplied to the sump10 from a washing pump (not shown) is disposed in the tub 11. The waterguide 100 is connected to the sump 20, extends rearward, and is bentaround the rear portion of the tub 11 and then extends upward.

The water guide 100 includes an upper pipe 110 that guides washing waterstored in the sump 200 to the upper nozzle 163 and a top pipe 120 thatguides washing water to the top nozzle 170. Washing water flowingthrough the upper pipe 110 and the top pipe 120 can be sprayed towardthe first rack 50 or the second rack 70 through the top nozzle 170 andthe upper nozzle 163. The upper pipe 110 and the top pipe 120 may bereferred in combination as to a “washing water pipe”.

The top pipe 120 may bend to the upper portion of the tub 11 and thenmay bend and extend forward from the upper portion of the tub 11. A topconnector 175 connected to the top nozzle 170 may be disposed at theupper portion of the top pipe 120.

A supply pipe 160 is connected to a substantially vertical middleportion of the water guide 100. The supply pipe 160 may extend forwardfrom the water guide 100 and may be connected to the upper nozzle 163.In detail, a nozzle holder 166 may be coupled to the supply pipe 160 andthe upper nozzle 163 may be coupled to the nozzle holder 166.

The upper nozzle 163 includes nozzle holes 163 a for spraying washingwater supplied to the upper nozzle 163 downward and upward from theupper nozzle 163. Several nozzle holes 163 are formed through the topand the bottom of the upper nozzle 163 and washing water can be sprayedtoward the first rack 50 or the second rack 70 through the nozzle holes163 a.

The water guide 100 further includes a holder 150 supporting the supplypipe 160. The holder 150 may be disposed at a substantially middleportion of the water guide 100 and may be coupled to the supply pipe160.

The water guide 100 further includes an upper connector 140 coupled tothe rear portion of the holder 150 and supporting the upper pipe 110 andthe top pipe 120, which will be described below.

The water guide 100 further includes a lower connector 130 disposed atthe lower portion of the water guide 100 and coupled to the sump. Thelower connector 130 may be understood as a part for connecting the upperpipe 110 and the top pipe 120 to the sump 20.

The configuration of the water guide 100 is described hereafter indetail with reference to the drawings.

FIG. 3 is a perspective view showing the configuration of the waterguide according to an embodiment of the present invention, FIG. 4 is across-sectional view taken along line IV-IV′ of FIG. 3, and FIG. 5 is anexploded perspective view showing the configuration of the water guideaccording to an embodiment of the present invention.

Referring to FIGS. 3 to 5, the water guide 100 according to anembodiment of the present invention includes a plurality of pipes 110and 120 connected to the sump 20 to guide washing water. The pipes 110and 120 includes an upper pipe 110 extending from the sump 20 to aheight around the center portion of the washing container and a top pipe120 extending from the sump 20 to a height around the ceiling of thewashing container.

The upper pipe 110 and the top pipe 120 may be arranged in parallelclose to each other up to the height around the center portion of thewashing container. The top pipe 120 may further extend up to a heightaround the ceiling from the center portion of the washing container.

The upper pipe 110 and the top pipe 120 may have bending shapes.

In detail, the upper pipe 110 extends rearward from the top of the sup20, bends upward around the rear portion of the washing container, andthen extends up to a height around the center portion of the washingcontainer. The upper pipe 110 includes a first up-bending portion 115disposed around the lower rear portion of the washing container. Thebending angle of the first up-bending portion 115 is about 90 degrees.The upper pipe 110 can have an L-shape by the first up-bending portion115.

The top pipe 120 extends rearward from the top of the sup 20, bendsupward around the rear portion of the washing container, and thenextends up to a height around the ceiling of the washing container. Thetop pipe 110 includes a plurality of bending portions.

In detail, the bending portions include a first top bending portion 125disposed around the lower rear portion of the washing container and asecond top bending portion 127 disposed around the upper rear portion ofthe washing container. The bending angles of the first and second topbending portions 115 are about 90 degrees. The top pipe 120 can have aU-shape by the first and second top bending portions 125 and 127.

The upper pipe 110 and the top pipe 120 each may have a polygonal pipeshape. For example, the upper pipe 110 and the top pipe 120 may have arectangular pipe shape. The polygonal pipe has the advantage that anavailable flow cross-section can be large relative to the installationvolume of the pipe, as compared with common circular pipes.

An upper channel 110 a through which washing water flows is formed inthe upper pipe 110. A top channel 120 a through which washing waterflows is formed in the top pipe 120. The upper channel 110 a and the topchannel 120 a each may form a substantially rectangular cross-section.

The upper channel 110 a may be formed greater in size than the topchannel 120 a. Accordingly, the amount of washing water that is suppliedto the upper nozzle 163 through the upper channel 110 a may be greaterthan the amount of washing water that is supplied to the top nozzle 170through the top channel 120 a. Accordingly, the amount of washing waterthat is sprayed from the upper nozzle 163 may be greater than the amountof washing water that is sprayed from the top nozzle 170.

The upper pipe 110 includes an upper inlet 111 into which washing watersupplied from the sump 20 is introduced and an upper outlet 112 throughwhich washing water flowing through the upper pipe 110 is discharged tothe upper connector 140. The upper inlet 111 may form an end of theupper pipe 110 and the upper outlet 112 may form the other end of theupper pipe 110.

The top pipe 120 includes a top inlet 121 into which washing watersupplied from the sump 20 is introduced and a top outlet 122 throughwhich washing water flowing through the top pipe 120 is discharged tothe top connector 175. The top inlet 121 may form an end of the top pipe120 and the top outlet 122 may form the other end of the top pipe 120.

The upper pipe 110 and the top pipe 120 may be stainless steel pipes.For example, a ductile stainless steel pipe having high strength andprocessibility may be included in the stainless steel pipes. Inparticular, the ductile stainless steel has a high flexibility, so itmay mean that bending processibility of the pipe is very high. Theductile stainless steel pipe may be made of a material including astainless material and impurities including at least copper (Cu).

The composition of the ductile stainless steel pipe is describedhereafter. It should be noted that the ratios of composition to bedescribed hereafter are expressed in weight percent (wt %).

1. Composition of Stainless Steel

(1) Carbon (C): 0.3% or less

The stainless steel for forming the water guide 100 and the pipes 110and 120 contains carbon (C) and chromium (Cr). Carbon is extracted aschromium carbide by reacting with chromium, in which exhaustion ofchromium at or around grain boundaries causes corrosion. Accordingly, itis preferable to maintain the content of carbon at a low level.

Carbon is an element that increases creep strength by bonding withanother element, and when the content of carbon exceeds 0.03%, ductileis deteriorated. Accordingly, the content of carbon is set at 0.03% orless in the present invention.

(2) Silicon (Si): more than 0 to 1.7% or less

Austenite has low yield strength as compared with ferrite or martensite.Accordingly, it is preferable that the matrix structure of the stainlesssteel is austenite in order that the ductile stainless steel of thepresent invention has flexibility (or degree of freedom of bending) at alever similar to or equal to that of copper.

However, because silicon is an element that forms ferrite, the higherthe content of silicon, the higher the ratio of ferrite in a matrixstructure, which increases the stability of ferrite. It is preferable tomaintain the content of silicon as low as possible, but it is impossibleto completely preventing silicon from being contained as an impurity ina manufacturing process.

When the content of silicon exceeds 1.7%, it is difficult to give arequired level of ductility to stainless steel and accordingly itbecomes difficult to secure sufficient processibility. Accordingly, thecontent of silicon that is contained in the stainless steel according toan embodiment of the present invention is set at 1.7% or less.

(3) Manganese (Mn): 1.5˜3.5%

Manganese suppresses a phase change of the matrix structure of stainlesssteel into a martensite type and contributes to stabilization byincreasing an austenite region. If the content of manganese is less than1.5%, a sufficient effect of the phase change suppression by manganesecannot be expected. Accordingly, the lower limit of the content ofmanganese is set at 1.5% to obtain a sufficient effect of the phasechange suppression by manganese.

However, the higher the content of manganese, the higher the yieldstrength of stainless steel, which decreases ductility of the stainlesssteel. Accordingly, the upper limit of the content of manganese is setat 3.5%.

(4) Chromium (Cr): 15˜18%

Chromium is an element that improves corrosion initiation resistance ofstainless steel. Corrosion initiation means occurrence of initialcorrosion without a base material corroded and corrosion initiationresistance means a property that suppresses initial corrosion of a basematerial. The corrosion initiation resistance can be construed as thesame meaning as corrosion resistance.

When the content of chromium is less than 15.0%, the stainless steelcannot have sufficient corrosion initiation resistance (or corrosionresistance), so the lower limit of the content of chromium is set at15.0% in the present invention.

However, when the content of chromium is too high, the phase changesinto ferrite in a room temperature, which reduces ductility. Further,particularly, stability of austenite is removed and the structure becomebrittle, which decreases strength. Therefore, the upper limit of thecontent of chromium is set at 18.0% in the present invention.

(5) Nickel (Ni): 7.0˜9.0%

Nickel has properties that improve corrosion growth resistance ofstainless steel and stabilizes austenite. Corrosion growth means thatcorrosion generated in a base material grows while spreading wide andcorrosion growth resistance means suppression of growth of corrosion.

When the content of nickel is less than 7.0%, the stainless steel cannothave sufficient corrosion growth resistance, so the lower limit of thecontent of nickel is set at 7.0% in the present invention. When thecontent of nickel is too high, the strength and hardness of thestainless steel are increased, so it becomes difficult to securesufficient processibility of the stainless steel. Further, the costs areincreased, which is economically disadvantageous. Therefore, the upperlimit of the content of nickel is set at 9.0% in the present invention.

(6) Copper (Cu): 1.0˜4.0% Copper increases ductility of stainless steelby suppressing a phase change of the matrix structure of the stainlesssteel into martensite. When the content of copper is less than 1.0%, asufficient effect of the phase change suppression by copper cannot beexpected. Accordingly, the lower limit of the content of copper is setat 1.0% to obtain a sufficient effect of the phase change suppression bycopper in the present invention. In particular, the content of coppermay be 1.0% or more to give a required level of flexibility to thestainless steel.

The higher the content of copper, the more the effect of phase changesuppression of a matrix structure, but the increasing amount graduallydecreases. When the content of copper is too high over 4˜45%, the effectis saturated and generation of martensite is promoted, so it is notadvantageous. Further, since copper is an expensive element, itinfluences economic efficiency. Therefore, the upper limit of thecontent of copper is set at 4.0% to maintain the effect of phase changesuppression by copper under the saturation level and to secureeconomical efficiency.

(7) Molybdenum (Mo): 0.03% or less

(8) Phosphorus (P): 0.04% or less

(9) Sulfur (S): 0.04% or less

(10) Nitrogen (N): 0.03% or less

Molybdenum, phosphorous, sulfur, and nitrogen, which are elementsalready contained in semi-finished steel products, harden stainlesssteel, so it is preferable to maintain the content of them as low aspossible.

2. Matrix Structure of Stainless Steel

Stainless steel, depending on the metal structure (or matrix structure),are classified into austenite type stainless steel having chromium (18%)and nickel (8%) as main components, ferrite type stainless steel havingchromium (18%) as a main component, and martensite type stainless steelhaving chromium (8%) as a main component.

Austenite type stainless steel having excellent corrosion resistanceagainst salt or acid and high ductility, so the ductile stainless steelof the present invention may be stainless steel of which the matrixstructure is an austenite type.

Further, the austenite structure has lower yield strength and hardnessthan those of the ferrite structure or the martensite structure.Furthermore, when the grain sizes are grown under the same condition,the average grain size of austenite is largest, which is advantageous inincreasing ductility.

It is preferable that the matrix structure of stainless steel is formedby only an austenite structure to increase ductility of stainless steel.However, it is very difficult to control the matrix structure ofstainless steel within only austenite, so other matrix structures areunavoidably included.

In detail, another matrix structure that influences ductility ofaustenite type stainless steel is δ-ferrite that is produced in a heattreatment process. That is, the greater the content of δ-ferrite, thehigher the hardness of stainless steel, but the lower the ductility.

It is preferable for stainless steel to have an austenite matrixstructure of over 90%, preferably, over 99% and a δ-ferrite matrixstructure of 1% with respect to the grain area. Accordingly, it may bepossible to reduce the amount of δ-ferrite contained in austenite typestainless steel as one of methods that increase ductility of stainlesssteel.

Even though ductility stainless steel according to an embodiment of thepresent invention has a δ-ferrite matrix structure of 1% or less, it isadvantageous for increase of ductility that the δ-ferrite is locallyconcentrated in specific grains rather than uniformly distributedthroughout the entire grains.

3. Average Grain Size (Average Diameter) of Stainless Steel

The average grain size of stainless steel may depend on the compositionand/or a heat treatment condition. The average grain size of stainlesssteel influences the strength and hardness of the stainless steel. Forexample, the smaller the average grain size, the higher the strength andhardness of stainless steel, and the greater the average grain size, thelower the strength and hardness of stainless steel.

Ductile stainless steel according to an embodiment of the presentinvention may be given high flexibility by adjusting the content ofcopper and the grain area of δ-ferrite. To this end, the average grainsize of the stainless steel is limited within 30˜60 μm. The averagegrain size of a common austenite structure is smaller than 30 μm.Accordingly, it is required to grow the average grain size over 30 μmthrough a manufacturing process and heat treatment.

According to the standards by American Society for Testing and Materials(ASTM), the average grain size of 30˜60 μm corresponds to grain sizeNos. 5.0˜7.0. However, the average grain size smaller than 30 μmcorresponds to a grain size No. 7.5 or more by ASTM.

The water guide 100 further includes the lower connector 130 connectingthe upper pipe 110 and the top pipe 120 to the sump 20. The lowerconnector 130 may be made of rubber.

For example, the lower connector 130 may be made of an EPDM material(EPDM rubber or ethylene propylene diene M-class rubber). The lowerconnector 130 may be configured such that the hardness of the frontportion connected to the sump 20 and the hardness of the rear portionconnected with the pipes 110 and 120 have different values. To this end,the lower connector 130 may be manufactured by multiple injectionmolding. This will be described below.

The water guide 100 further includes a clamp 180 coupled to the lowerconnector 130. It is possible to prevent the pipes 110 and 120 fromseparating from the lower connector 130 by tightening the clamp 180.

The water guide 100 further includes the upper connector 140 supportingthe upper pipe 110 and the top pipe 120. The upper connector 140 may bedisposed at the height of the center portion of the washing container.

In detail, the upper connector 140 includes a connector body 141 towhich the upper pipe 110 is coupled. A connector outlet 143 fordischarging washing water supplied from the upper pipe 110 may bedisposed on the front surface of the connector body 141.

The water guide 100 further includes the holder 150 disposed ahead ofthe upper connector 140 and supporting the supply pipe 160. The holder150 includes a holder body 151 coupled to the upper connector 140 andhaving a pipe communicating portion 153 communicating with the connectoroutlet 143. The supply pipe 160 can be coupled to the pipe communicatingportion 153.

The holder 150 includes a rack supporting portion 155 disposed on bothsides of the holder body 151 and supporting the first rack 50. The racksupporting portion 155 may include a plurality of rack supportingportions vertically spaced apart from one another. The first rack 50 canbe installed at a predetermined height by being supported by one of therack supporting portions.

The water guide 100 further includes a bracket 190 for fixing the toppipe 120 to the upper connector 140. The top pipe 120 can be seated onthe upper connector 140 and the bracket 190 is coupled to the outer sideof the top pipe 120, thereby being able to keep the top pipe 120 inclose contact with the upper connector 140.

FIG. 6 is a rear view showing the upper pipe and the top pipe coupled tothe upper connector and the holder according to an embodiment of thepresent invention, FIG. 7 is a view showing the bracket coupled to theupper connector according to an embodiment of the present invention,FIG. 8 is a rear view showing the upper pipe and the top pipe coupled tothe upper connector according to an embodiment of the present invention,and FIG. 9 is a cross-sectional view taken along line IX-IX′ of FIG. 8.

Referring to FIGS. 6 to 9, the upper pipe 110 and the top pipe 120according to an embodiment of the present invention are coupled to theupper connector 140. The upper connector 140 may be made of plastic. Forexample, the upper connector 140 may be made of PP (Polypropylene).

In detail, the connector body 141 of the upper connector 140 includes apipe coupling portion 142 to which the upper pipe 110 is coupled. Theupper pipe 110 is inserted in the pipe coupling portion 142 and the pipecoupling portion 142 may have a polygonal pocket shape to be able toreceive the upper pipe 110. For example, the upper pipe 110 may beinserted from the lower end of the pipe coupling portion 142 and thenmay extend upward.

A connector channel 141 a through which washing water flows is formed inthe connector body 141. The connector channel 141 a can guide washingwater discharged from the upper pipe 110 to the connector outlet 143.That is, the connector channel 141 a may extend to the connector outlet143 from the outlet of the upper outlet 112 of the upper pipe 110.

Water discharged upward from the upper pipe 110 can flow forward towardthe connector outlet 143 through the connector channel 141 a. That is,the flow direction of washing water is changed in the connector channel141 a, so a round portion 143 a may be formed on the inner side of theconnector outlet 143 to reduce flow resistance. The round portion 143 ais formed such that the inner side of the connector body 141 can besmoothly bent in the front-rear direction from the up-down direction. Inorder to achieve the round portion 143 a, the upper connector 140 may bemanufactured by double injection molding.

The upper pipe 110 may be forcibly fitted in the pipe coupling portion142. Water discharged from the upper channel of the upper pipe 110 flowsinto the connector channel 141 a of the upper connector 140. In thisprocess, there is a possibility of leakage of washing water.Accordingly, the upper pipe 110 is brought in close contact with thepipe coupling portion 142 by forcible fitting, so leakage of washingwater at the joint between the upper pipe 110 and the upper connector140 can be prevented.

The connector body 141 of the upper connector 140 includes a pipeinserting portion 145 in which the top pipe 120 is inserted. The pipeinserting portion 145 is recessed forward from the rear side of theconnector body 141 and vertically extends to correspond to the extensiondirection of the top pipe 120.

The water guide 100 further includes the bracket 190 coupled to the rearside of the top pipe 120 and supporting the top pipe 120. The bracket190 may have a bent shape to surround at least a portion of the rearside and at least a portion of the lateral sides of the connector body141. For example, the bracket 190 may include a bracket rear sidesurrounding at least a portion of the rear side of the connector body141 and two bracket lateral sides surrounding at least a portion of bothlateral sides of the connector body 141.

The bracket 190 includes a hook insert 192 fitted to a hook 147 of theconnector body 141. The hook insert 192 is formed through at least aportion of the two bracket lateral sides and the hook 147 can beinserted in the hook insert 192. The hook 147 protrudes from bothlateral sides of the connector body 141.

The upper connector 141 further includes a pipe supporting portion 146for supporting the top pipe 120. The pipe supporting portion 146 mayprotrude from the rear side of the connector body 141 toward the pipeinserting portion 145 to support the rear side of the top pipe 120.

The upper connector 141 further includes pipe coupling portions 148coupled to the holder 150. The holder coupling portions 148 may protrudeoutward from the lateral sides of the connector body 141 to be coupledto the holder 150. For example, the holding coupling portions 148 mayinclude protrusions and the protrusions may be inserted in the holder150.

FIG. 10 is a view showing the upper pipe and the top pipe connected tothe sump through the lower connector according to an embodiment of thepresent invention, FIG. 11 is a cross-sectional view taken along lineXI-XI′ of FIG. 10, FIG. 12 is a cross-sectional view taken along lineXII-XII′ of FIG. 10, and FIG. 13 is a plan view showing the upper pipeand the top pipe coupled to the lower connector according to anembodiment of the present invention.

Referring to FIGS. 10 and 12 first, the upper pipe 110 and the top pipe120 according to an embodiment of the present invention may be coupledto the sump 20 through the lower connector 130.

The sump 20 includes sump inlets 20 a on the top thereof through whichwashing water flows into the sump 20. The lower connector 130 may becoupled to the top of the sump 20 a, and the upper pipe 110 and the toppipe 120 may be coupled to the lower connector 130.

The lower connector 130 includes an upper pipe connecting portion 131connected with the upper pipe 110 and a top pipe connecting portion 133connected with the top pipe 120. For the convenience of description, theupper pipe connecting portion 131 may be referred to as a “firstconnecting portion” and the top pipe connecting portion 133 may bereferred to as a “second connecting portion”.

The upper pipe connecting portion 131 and the top pipe connectingportion 133 may be integrally formed by injection molding. The lowerconnector 130 includes a separation wall 137 that separates the upperpipe connecting portion 131 and the top pipe connecting portion 133. Theseparation wall 137 may be disposed between the upper pipe connectingportion 131 and the top pipe connecting portion 133. A washing waterchannel in the upper pipe connecting portion 131 and a washing waterchannel in the top pipe connecting portion 133 can be separated by theseparation wall 137.

In detail, a first channel that guides washing water to the upper pipe110 is formed in the upper pipe connecting portion 131 and a secondchannel that guides washing water to the top pipe 120 is formed in thetop pipe connecting portion 133. The first and second channels can beseparated from each other by the separation wall 137.

The first channel of the upper pipe connecting portion 131 may be formedgreater than the second channel of the top pipe connecting portion 133.The size of the upper pipe connecting portion 131 may be greater thanthe size of the top pipe connecting portion 133.

The upper pipe 110 is coupled to the rear portion of the upper pipeconnecting portion 131. For example, the upper pipe 110 may be insertedin the rear portion of the upper pipe connecting portion 131. The toppipe 120 is coupled to the rear portion of the top pipe connectingportion 133. For example, the top pipe 120 may be inserted in the rearportion of the top pipe connecting portion 133.

The front portion of the upper pipe connecting portion 131 is coupled tothe top of the sump 20. The sump 20 includes a first outlet 22 fordischarging the washing water stored in the sump 20 from the sump 20.The first outlet 22 is recessed down from the top of the sump 20 and maycommunicate with a washing water storage space in the sump 20.

The upper pipe connecting portion 131 includes a first sump couplingportion 132 coupled to the first outlet 22. The first sump couplingportion 132 may vertically extend at the front portion of the upper pipeconnecting portion 131 and may extend into the first outlet 22 fromabove the first outlet 22. Accordingly, the washing water stored in thesump 20 can flow into the upper pipe connecting portion 131 through thefirst outlet 22 and the first sump coupling portion 132.

The front portion of the top pipe connecting portion 133 is coupled tothe top of the sump 20. The sump 20 includes a second outlet 23 fordischarging the washing water stored in the sump 20 from the sump 20.The second outlet 23 may be formed at a predetermined distance from thefirst outlet 22. The second outlet 23 is recessed down from the top ofthe sump 20 and may communicate with a washing water storage space inthe sump 20.

The top pipe connecting portion 133 includes a second sump couplingportion 134 coupled to the second outlet 23. The second sump couplingportion 134 may vertically extend at the front portion of the top pipeconnecting portion 133 and may extend into the second outlet 23 fromabove the second outlet 23. Accordingly, the washing water stored in thesump 20 can flow into the top pipe connecting portion 133 through thesecond outlet 23 and the second sump coupling portion 134.

The sump 20 further includes a channel separator 25 that separates thefirst outlet 22 and the second outlet 23. The channel separator 25 maybe disposed between the first outlet 22 and the second outlet 23.Washing water stored in the sump 20 can be divided and dischargedthrough the first outlet 22 and the second outlet 23 by the channelseparator 25.

The water guide 100 further includes the clamp 180 coupled to the lowerconnector 130 and keeping the upper pipe 110 and the top pipe 120 inclose contact with the lower connector 130.

The clamp 180 may be coupled to the rear portion of the lower connector130. In detail, the clamp 180 may be disposed to surround the portion inwhich the upper pipe 110 and the top pipe 120 are inserted of the rearportion of the lower connector 130, that is, the outer side of a clampcoupling portion 135.

The clamp 180 may be disposed in contact with the clamp coupling portion135. At least a portion of the clamp coupling portion 135 may constitutethe upper pipe connecting portion 131 and the other portion mayconstitute the top pipe connecting portion 133.

Referring to FIG. 13, the lower connector 130 may be made of rubber. Forexample, the lower connector 130 may be made of an EPDM material (EPDMrubber or ethylene propylene diene M-class rubber)

The lower connector 130 may have portions having different hardness bymultiple injection molding. The lower connector 130 includes aconnector-front portion 130 a including the portion coupled to the sump20 and a connector-rear portion 130 b including the portion coupled tothe top pipe 120.

The connector-front portion 130 a and the connector-rear portion 130 bcan be separated by a first extension line That is, the connector-frontportion 130 a is a portion defined ahead of the first extension line l₁and the connector-rear portion 130 b is a portion defined behind thefirst extension line l₁. At least a portion of the connector-frontportion 130 a may constitute the upper pipe connecting portion 131 andthe other portion may constitute the top pipe connecting portion 133.

The hardness of the connector-front portion 130 a may be higher than thehardness of the connector-rear portion 130 b.

In detail, the connector-front portion 130 a may have relatively highhardness to be stably coupled to the sump 20. For example, the hardnessof the connector-front portion 130 a may be 90 in shore hardness. Sincethe connector-front portion 130 a has high hardness, it is possible toprevent the lower connector 130 from separating from the sump 20.

The connector-rear portion 130 b may have relatively low hardness toprevent leakage of washing water. For example, the hardness of theconnector-rear portion 130 b may be 60 in shore hardness. Since theconnector-rear portion 130 b has low hardness, the lower connector 130can be brought in closer contact with the upper pipe 110 and the toppipe 120, so leakage of washing water at the joint between the lowerconnector 130 and the pipes 110 and 120 can be prevented.

The connector-rear portion 130 b includes the clamp coupling portion 135to which the clamp 180 is coupled and a connector extending portion 139extending rearward from the clamp coupling portion 135. The connectorextending portion 139 constitute the upper pipe connecting portion 131.

That is, the length of the rear portion of the upper pipe connectingportion 131 may be greater than that of the rear portion of the top pipeconnecting portion 133 by the front-rear length L1 of the connectingextending portion 139. This is for more strongly sealing the jointbetween the upper pipe 110 and the upper pipe connecting portion 131because more washing water flows through the upper pipe connectingportion 131 than the top pipe connecting portion 133.

Accordingly, the contact area between the upper pipe 110 and the upperpipe connecting portion 131 may be greater than the contact area betweenthe top pipe 120 and the top pipe connecting portion 133 by theconnector extending portion 139.

The connector extending portion 139 has a protrusion 136. The protrusion136 is formed on the outer surface of the connector extending portion139. The protrusion 136 can reduce the amount of deformation of theupper pipe connecting portion 131 when the upper pipe connecting portion131 is deformed by the pressure of the washing water flowing through theupper pipe 110. That is, the elasticity of the upper pipe connectingportion 131 can be increased and the strength of the upper pipeconnecting portion 131 can be correspondingly improved by the protrusion136. A plurality of protrusions 136 may be provided and they may bespaced apart from one another in the front-rear direction.

FIG. 14 is a perspective view showing the clamp coupled to the lowerconnector according to an embodiment of the present invention and FIGS.15A and 15B are views showing the configuration of the clamp accordingto an embodiment of the present invention.

Referring to FIGS. 14 to 15B, the clamp 180 is coupled to the lowerconnector 130 according to an embodiment of the present invention. Theclamp 180 may be made of a plate-shaped elastic material. For example,the clamp 180 may include a plate-shaped spring.

The clamp 180 may be formed relatively thin to prevent interference bythe lower nozzle 17. For example, the thickness of the clamp 180 may bein the range of 0.4˜0.6 mm.

The clamp 180 may have a bent shape. In detail, the clamp 180 includes afirst part 181 a that is placed on the top of the lower connector 130, asecond part 181 b that bends downward from a side of the first part 181a and is placed on a lateral side of the lower connector 130, and athird part 181 c that bends from the second part 181 b and is placed onthe bottom of the lower connector 130.

The clamp 180 further includes a first locking portion 182 bendingdownward from the other side of the first part 181 a and a secondlocking portion 183 bending upward from the third part 181 c to belocked to the first locking portion 182.

When the clamp 180 is not coupled yet to the lower connector 130, thefirst and second locking portions 182 and 183 may be spaced apart fromeach other without locking to each other. That is, the first lockingportion 182 may be spaced upward apart from the second locking portion183.

When the first locking portion 182 and the second locking portion 183are closed with the clamp 180 fitted on the lower connector 130, thefirst locking portion 182 and the second locking portion 183 can belocked to each other.

The first locking portion 182 may include a first protrusion 182 a andthe second locking portion 183 may include a second protrusion 183 a.The first protrusion 182 a and the second protrusion 183 a may protrudelaterally from lateral sides of the first and second locking portions182 and 183. The first protrusion 182 a may be locked to the secondlocking portion 183 a under the second locking portion 183 a. That is,the top of the first locking portion 182 a may be supported by thebottom of the second locking portion 183 a.

According to this configuration, the clamp 180 can be easily coupled toand separated from the lower connector 130 and the tightening force ofthe clamp 180 can be easily transmitted to the upper pipe 110 and thetop pipe 120 through the lower connector 130.

FIG. 16 is a flowchart showing a method of manufacturing a pipeaccording to an embodiment of the present invention. A method ofmanufacturing the upper pipe 110 or the top pipe 120 according to anembodiment of the present invention is described with reference to FIG.16.

First, it is possible to manufacture a circular pipe using a stainlessmaterial that is a raw material. The stainless material may includeductile stainless steel described above,

In detail, a plate made of a stainless material that is a raw materialis rolled and both bonding ends of the rolled plate can be bonded by gaswelding. The bonding portions are cooled and polished, and then acircular pipe is taken out. The taken circular pipe is cut in anappropriate size (S11).

A polygonal pipe, for example, a rectangular pipe is obtained byperforming drawing on the processed circular pipe and is then cut in anappropriate size. The rectangular pipe may be manufactured to haveinner/outer sizes corresponding to the upper pipe 110 and the top pipe120.

The upper pipe 110 and the top pipe 120 for the water guide according tothe present invention can be manufactured by performing bending on themanufactured rectangular pipe. Bending can be performed by a polygonalmandrel.

Since bending of a pipe is performed using ductile stainless steel, asdescribed above, elongation and processibility of a pipe can beimproved. Accordingly, the first and second bending portions 115 and 125of the pipes 110 and 120 can be easily achieved and stress corrosion atthe first and second bending portions 115 and 125 can be reduced, sodamage to the pipes 110 and 120 can be prevented (S13).

FIG. 17 is a perspective view showing a clamp coupled to a lowerconnector according to another embodiment of the present invention andFIG. 18 is a view showing the configuration of the clamp of FIG. 17.

Referring to FIGS. 17 and 18, a clamp 280 is coupled to a lowerconnector 230 according to another embodiment of the present invention.The clamp 280 may be made of an elastic material. For example, the clamp280 may include a spring wire.

The clamp 280 may be formed relatively thin to prevent interference bythe lower nozzle 17. For example, the thickness of the clamp 20 may bein the range of 0.4˜0.6 mm.

The lower connector 230 includes an upper pipe connecting portion 231 towhich the upper pipe 110 is coupled and a top pipe connecting portion233 to which the top pipe 120 is coupled. The upper pipe connectingportion 231 and the top pipe connecting portion 233 form separatewashing water channels.

A protrusion 236 for increasing elasticity of the upper pipe connectingportion 231 and the top pipe connecting portion 233 may be formed at therear portion of the upper pipe connecting portion 231 and the rearportion of the top pipe connecting portion 233. The protrusion 236protrudes from the upper pipe connecting portion 231 and the top pipeconnecting portion 233 and a plurality of protrusions may be provided.

The upper pipe connecting portion 231 has a clamp coupling portion 235to which the clamp 280 is coupled. The clamp coupling portion 235 mayinclude grooves formed between the plurality of protrusions 236 on theupper pipe connecting portion 231. The clamp 280 may be coupled to theouter surface of the upper pipe connecting portion 231 by being insertedin the grooves. By this configuration, the clamp 280 can firmly fix theupper pipe 110 coupled to the upper pipe connecting portion 231.

The clamp 280 may have a bent shape. In detail, the clamp 280 includes afirst part 281 a that is placed on the top of the lower connector 230, asecond part 281 b that bends downward from a side of the first part 281a and is placed on a lateral side of the lower connector 230, and athird part 281 c that bends from the second part 281 b and is placed onthe bottom of the lower connector 230.

The clamp 280 further includes a first locking portion 282 bendingdownward from the other side of the first part 281 a and a secondlocking portion 283 bending upward from the third part 281 c to belocked to the first locking portion 282.

When the clamp 280 is coupled to the lower connector 230, the first andsecond locking portions 282 and 283 can be opened away from each other,so the clamp 280 can be fitted to the clamp coupling portion 235.

When the clamp 280 is fitted to the lower connector 230, the firstlocking portion 282 and the second locking portion 283 can be locked toeach other by returning force.

According to this configuration, the clamp 280 can be easily coupled toand separated from the lower connector 230 and the tightening force ofthe clamp 280 can be easily transmitted to the upper pipe 110 throughthe lower connector 230.

FIG. 19 is a perspective view showing a clamp coupled to a lowerconnector according to another embodiment of the present invention.

Referring to FIG. 19, a clamp 380 is coupled to a lower connector 330according to another embodiment of the present invention. The clamp 380may be made of an elastic material. For example, the clamp 380 includesa spring wire and may have the same configuration as the clamp describedwith reference to FIG. 18.

The lower connector 330 includes an upper pipe connecting portion 331 towhich the upper pipe 110 is coupled and a top pipe connecting portion333 to which the top pipe 120 is coupled. The upper pipe connectingportion 331 and the top pipe connecting portion 333 form separatewashing water channels.

A protrusion 336 for increasing elasticity of the upper pipe connectingportion 331 and the top pipe connecting portion 333 may be formed at therear portion of the upper pipe connecting portion 331 and the rearportion of the top pipe connecting portion 333. The protrusion 236protrudes from the upper pipe connecting portion 331 and the top pipeconnecting portion 333 and a plurality of protrusions may be provided.

The upper pipe connecting portion 331 and the top pipe connectingportion 333 have a clamp coupling portion 335 to which the clamp 380 iscoupled. The clamp coupling portion 335 may include grooves formedbetween the plurality of protrusions 236 on the upper pipe connectingportion 331 and the top pipe connecting portion 333.

The clamp 380 may be coupled to the outer surfaces of the upper pipeconnecting portion 331 and the top pipe connecting portion 333 by beinginserted in the grooves. By this configuration, the clamp 380 can firmlyfix the upper pipe 110 coupled to the upper pipe connecting portion 331and the top pipe 120 coupled to the top pipe connecting portion 333.

According to this configuration, the clamp 380 can be easily coupled toand separated from the lower connector 330 and the tightening force ofthe clamp 380 can be easily transmitted to the upper pipe 110 and thetop pipe 120 through the lower connector 330.

What is claimed is:
 1. A dishwasher comprising: a washing containerconfigured to receive one or more objects to be washed; a sump disposedat a lower portion of the washing container and configured to storewashing water; an upper nozzle disposed at a center portion of thewashing container and configured to spray washing water supplied fromthe sump to the washing container; a top nozzle that is disposed at anupper portion of the washing container, that is positioned verticallyabove the upper nozzle, and that is configured to spray washing watersupplied from the sump to the washing container; and a water guide thatextends upward from the sump and that is configured to supply washingwater to the upper nozzle and to the top nozzle, the water guidecomprising: an upper pipe having an upper inlet configured to receivewashing water from a first outlet of the sump, and an upper outletconfigured to supply washing water to the upper nozzle, a top pipe thatis separately disposed at a side of the upper pipe and that isconfigured to receive washing water from a second outlet of the sump tosupply washing water to the top nozzle, and an upper connector thatsupports the upper pipe and the top pipe, the upper connector includinga connector body that is coupled to the upper pipe, wherein theconnector body defines: a connector channel configured to guide washingwater discharged through the upper outlet of the upper pipe, a connectoroutlet configured to discharge washing water guided through theconnector channel, a pipe coupling portion that receives the upperoutlet of the upper pipe and that is configured to supply washing waterdischarged from the upper outlet toward the connector outlet through theconnector channel, and a pipe inserting portion that receives the toppipe, wherein the upper pipe is fitted into the pipe coupling portionsuch that the upper outlet and the connector channel are incommunication with each other, wherein the upper connector furtherincludes a pipe supporting portion that protrudes from a rear side ofthe connector body toward the pipe inserting portion, the pipesupporting portion supporting a rear side of the top pipe, wherein theconnector body comprises hooks that protrude from lateral sides of theconnector body, respectively, wherein the dishwasher further comprises abracket that is coupled to the upper connector and supports the rearside of the top pipe, the bracket comprising: a bracket rear side thatcovers at least a portion of the rear side of the connector body and therear side of the top pipe, bracket lateral sides that cover at least aportion of the lateral sides of the connector body, respectively, andhook inserts that are defined at the bracket lateral sides,respectively, each of the hook inserts receiving one of the hooks of theconnector body, wherein an inner surface of the pipe coupling portiondefines a recess that is stepped relative to an inner surface of theconnector body and that receives an upper portion of the upper pipe,wherein a distal end of the upper pipe is in contact with an upper endof the recess and configured to block leakage of washing water, theupper end of the recess being disposed vertically below the connectoroutlet, and wherein a depth of the recess is equal to a thickness of theupper pipe such that the inner surface of the connector body is coplanarwith an inner surface of the upper portion of the upper pipe to therebyminimize a flow resistance of washing water flowing along the upper pipeand the upper connector.
 2. The dishwasher of claim 1, wherein the upperoutlet is disposed inside the pipe coupling portion.
 3. The dishwasherof claim 1, wherein the bracket has a bent shape that surrounds at leasta portion of a rear side of the upper connector and at least a portionof both lateral sides of the upper connector.
 4. The dishwasher of claim1, wherein the connector outlet is disposed at a front surface of theconnector body, and has a round shape that extends from the connectorchannel.
 5. The dishwasher of claim 4, further comprising: a holdercoupled to the upper connector, the holder comprising a pipecommunicating portion that is in communication with the connectoroutlet; and a supply pipe that is coupled to the pipe communicatingportion and that extends toward the upper nozzle.
 6. The dishwasher ofclaim 1, wherein the top pipe comprises a top pipe inlet configured toreceive washing water from the second outlet of the sump, and a top pipeoutlet configured to discharge washing water from the top pipe, andwherein the dishwasher further comprises a top connector that allowscommunication between the top pipe outlet and the top nozzle.
 7. Thedishwasher of claim 1, wherein at least one of the upper pipe or the toppipe is made of a stainless material.
 8. The dishwasher of claim 1,wherein at least one of the upper pipe or the top pipe is a stainlesssteel pipe made of a stainless material and impurities including carbon,manganese, chromium, nickel, and copper.
 9. The dishwasher of claim 1,further comprising: an upper pipe bending portion disposed at the upperpipe and configured to change a first flow direction of washing water inthe upper pipe; and a first top pipe bending portion and a second toppipe bending portion that are disposed at the top pipe, each of thefirst and second top pipe bending portions being configured to change asecond flow direction of washing water in the top pipe.
 10. Thedishwasher of claim 1, wherein at least one of the upper pipe or the toppipe has a polygonal shape.
 11. The dishwasher of claim 1, wherein achannel cross-sectional area of the upper pipe is greater than a channelcross-sectional area of the top pipe.
 12. The dishwasher of claim 1,wherein the upper pipe extends together with the top pipe to the upperconnector, and the upper pipe is configured to discharge washing waterto the connector channel in the upper connector, and wherein the toppipe passes through the upper connector to connect to the top nozzle.13. The dishwasher of claim 1, wherein the connector outlet ispositioned vertically above the upper outlet of the upper pipe locatedinside the upper connector.
 14. The dishwasher of claim 1, wherein thepipe inserting portion is recessed forward relative to the rear side ofthe connector body and vertically extends along an extension directionof the top pipe.
 15. The dishwasher of claim 14, wherein the connectorbody covers at least a portion of a front side of each of the upper pipeand the top pipe.
 16. The dishwasher of claim 1, wherein the distal endof the upper pipe is received inside the connector body and defines theupper outlet in an upward direction facing the top pipe.